Mondo and MTN horrible service!

Struggling for 3 weeks with a cancellation and still no response! My new device was delivered on 1 November, upon which I connected it and waited 48 hours for simcard to register. The speed was only 10mbs and what was sold to me was 50mbs, so I phoned and asked what the return procedure is. Following their instructions, I returned the device to an MTN outlet on the 5th, got the IRMS number and was told I had to phone Mondo with that info which I did on the 7th. From then until today 28 November I still have not been able to confirm the cancellation. And best of all MTN wants to deduct their first debit order on the 30th. Mondo blames MTN because the device has not been found in their warehouse to confirm cancellation, and MTN cannot help me because I have to handle the cancellation with Mondo. Absolutely disgusted by this experience with the horrible service I have received.